Apparatus comprising baffles and inflatable air foils for drying lumber



July 27, 1965 s. c. SMITH 3 1 APPARATUS COMPRISING BAFFLES AND INFLATABLE AIR FOILS FOR DRYING LUMBER 1959 4 Sheets-Sheet 1 Original Filed June 30,

KSAMUEL CARLTON SMITH W ATTORNEYS y 27, 1965 s. c. SMITH 3,196,554

APPARATUS COMPRISING BAFFLES AND INFLATABLE FOILS FOR DRYING LUMBER 4 Sheets-Sheet 2 Original Filed June 30,

INVENTOR ATTORNEY) July 27, 1965 s. c. SMITH 3,196,554

APPARATUS COMPRISING BAFFLES AND INFLATABLE AIR FOILS FOR DRYING LUMBER Original Filed June 30, 1959 4 t ee 5 INVENTOR SAMUEL CARLTON SMITH r71 gmu/wn, 71%

ATTORNEY July 27, 1965 c SMITH 3,156,554

S. APPARATUS COMPRISING BAFFLES AND INFLATABLE AIR FOILS FOR DRYING LUMBER Original Filed June 30, 1959 ---Fl .6. im G I Q G e Q i 33 7.

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'7 SAMUEL CARLTON SMITH 50 BY 9 9 9 i i Z20 44o W W2 L I: I I CURRENT SUPPLY I 4 Sheets-Sheet 4 United States Patent 3,196,554 APPARATUS CQRISING BAFFLES AND W- FLATABLE AIR FGILS FOR DRYENG LUMBER Samuel Carlton Smith, Memphis, Tenn, assignor to Fan- Air Systems, Inc, Memphis, Team, a corporation of Tennessee Original application June 30, 1959, Ser. No. 323,892, new Patent No. 3,090,130, dated May 21, 1963. Divided and this application July 26, 1962, Ser. No. 212,637

4 Claims. (Cl. 3450) This application is a division of my application, Serial No. 823,892, filed June 30, 1959, now Patent No. 3,090,- 130, issued May 21, 1963 for Lumber Drying Apparatus and Method.

This invention relates to an improved apparatus and method for initially drying green lumber, both hard and soft wood, after sawing, to prepare it for subsequent final drying in a kiln.

Lumber green from the saw is in its natural state and is free from stresses. At this point its moisture content is too high for most uses. It is a primary object of this invention to provide a first stage of drying in which the moisture content of all the boards in a stockpile is lowered uniformly to prevent warp, twist, end checks and stains and to thus provide a product in optimum condi tion for the final kiln drying.

For many years the lumber industry has made a practice of stockpiling green lumber, after sawing, in open yards to initially dry it and prepare the lumber for final drying. This drying period is normally from three to four months in the lumberyard and has many limitations and drawbacks. A prime objection to this method of drying lumber is the time required to dry it down to the desired moisture content. Further, due to exposure, heat and uneven drying Warpage, twisting, checks and stains resuit, all of which degrade the lumber, decrease its ultimate value and cause a high percent of loss. The investment necessary in lumberyard area, tie up of operating capital and deterioration of lumber in the yard are all factors against this conventional method of drying.

It is therefore a primary object of this invention to evolve an apparatus and drying method which will eliminate all of the foregoing drawbacks and which will accomplish optimum preliminary drying of freshly sawed green lumber in a small fraction of the time previously required.

It is a further object of the invention to evolve a system of fast, emcient and controlled drying of green lumber which will produce a product of much higher quality than was previously possible and will do so in a predictable and greatly reduced period of time.

The system broadly comprises the shielding of the stockpile of lumber in comparatively small enclosures by means of a flexible and conformable fireproof cover and the controlled drawing of atmospheric air at desired hurnidity and at a constant velocity through the stockpile of lumber by means of a bank of fans, to expedite the drying operation. The fans are preferably electrically operated by individual electric motors through a controlled circuit which is responsive to the humidity of the atmospheri-c air, whereby fan operation is stopped whenever the humidity of the air is either too high or too low for optimum results.

As shown in the drawings, the outer end of the cover or enclosure for the stockpile of lumber is open to the atmosphere and the inner end thereof is enclosed by a wall or panel, providing a housing for the fans which draw the atmospheric air through the stockpile at a constant velocity and exhaust it thereafter to the atmosphere. An appropriate control box is provided adjacent the 3,19,554 Patented July 27, 1965 "ice housing or cover to control the operation of the fans, as will hereinafter be discussed at more length.

In another embodiment of the invention, where the apparatus is installed within -a conventional building or walled shed the shroud or cover may be eliminated and appropriate swinging baflies, vertically disposed along the walls and ceiling thereof may 'be substituted for the shroud, as will hereinafter be discussed at more length. In this embodiment of the invention the outer extremity of the shed or housing is left open to the atmosphere and the inner, opposite extremity is enclosed, providing a housing for the bank of air fans which pull atmospheric air through the open end of the shed, through the stockpile of lumber and then exhaust it through the rear wall to the atmosphere. In this embodiment of the invention, also, an appropriate control box is provided, including humidostats to control the operation of the fan bank in accordance with the humidity of the atmosphere.

In most instances, and dependent upon atmospheric conditions, lumber processed by the present method is ready for kilning in from five to ten days, dried to the accepted standards of the lumber industry.

In this installation atmospheric air is drawn through the stockpile of lumber only at such times as its humidity is such that a potential for removing moisture from the lumber exists. Normally, the humidostat controlling the fans is set to stop the fans when the relative humidity of the air reaches approximately R.H. and to start them when the humidity of the outside air falls below 95% RE.

The flexible covering provides a highly efficient and low cost means of channeling the air directly through the layers of lumber and as it is flexible it may be drawn to enclose the outer contour of the stockpile closely to insure uniform movement of air over all lumber surfaces. Further, the flexible covering protects the stockpile from rain and from the direct rays of the sun and thus eliminates unequal drying conditions in the stockpile. It thus greatly accelerates uniform drying of all the lumber, regardless of its position in the stockpile, and this rapid and uniform drying eliminates twisting, warping, checks and stains in the lumber. The ultimate product of this novel drying installation is uniformly dried and of much higher quality, with practically no spoil-age, than lumber which is conventionally stockpiled in yards Where it is exposed to all types of weather conditions and wide variations in atmospheric humidity and temperature.

Referring to the drawings, FIG. 1 is a perspective view, partially in phantom, of one embodiment of the invention utilizing a flexible, fireproof cover, showing the bank of fans in the rear wall of the structure and the control box and circuit therefor; FIG. 2 is a perspective view, partially in phantom, of an alternative embodiment of the invention incorporating hinged, air foil baflies in a substantially rectangular building structure, including side and rear walls and a roof; FIG. 3 is a perspective view, partially broken away and in phantom, of the roof section of the embodiment of the invention shown in FIG. 2; FIG. 4 is a cross-sectional view from above, taken on line 4-4 of FIG. 2, of one of the air foil baffles of FIG. 2, showing the manner of air ingress and the conforming of the inflated canvas extremity thereof to the contour of the stockpile; FIG. 5 is a partial detailed view of one embodiment of a mechanical control means for maintaining the ceiling air foil baffles in inoperative position; FIG. 6 is an end view of the fan bank extremity of the embodiment shown in FIG. 1; FIG. 7 is a perspective view of the control box structure for the fan circuit and FIG. 8 is a schematic view of the fan motor circuit and controls therefor.

Referring to the drawings, FIG. 1, S indicates a stockamoeba pile of lumber which is preferably arranged in a substantially, rectangular form, the individual layers of boards being appropriately'separated by, spacers, as is conventional, to provide air space between the individual layers of boards. Outer cover or canopy. 10, preferably formed 7 of heavy fireproof canvas or analagous material, is shown closely fitted and extending downwardly over stockpile 'S to closely engage the-outer edges thereof. Canopy 10 is supported in position over stockpile S by means of an outer frame llfcornposed of vertical side poles connected by lateral cross membersat their upper extremities and fixed at'intervals to the outer surfaces of cover 10. As shown, outer frame 11 is preferably composed of some four identical sets of vertically disposed poles 13 and 14 set in'the ground at'their lower extremities and joined at their tops by cross braces'15 fixedbetween the upper extremities of poles 13 and 14 and extending across the upper surface of cover 1 0. Alongitudinal ridgepol'e, as shown, preferably joins the sets of frames at the centers of cross braces 15, to which it is appropriately nailed, or

otherwise aff xed.

Attached adjacent the upperextremities of vertical poles 13 and 14 are pulleys 16 and 17 over which are respec-" tively passed supporting lines 18 and 19 whichare-utili'zed to raise and lower cover 105 and to insure a close fit thereof over the stockpile S. A series of eyelets or rings 20 and 21 are appropriately stitched or otherwise affixed at intervals to cover 10 and extend from the upper lateral edges, respectively, at both sides of cover 10 downwardly to its lower or bottom'edge, lines 18 and 10 being passed therethrough and affixed to the lowest eyelets at the bottom edge of cover 10' As shown, rings, 20 and '21 are arranged .at equal intervalsthe length" of'cover 10,

four sets thereof being preferablyutilizedfl The outer ends of-lines'18 and 19 are preferably affixed about apports 13 for canopy l0 and is so placed as to be freely accessiblefrom the outside to control the operation of fans 35 in conformity with the atmospheric humidity and other factors. Control box 36 and the control circuit to the fan motors areshown, respectively, in FIGS; 7 and 8 of, the drawings and will be described in detail further on in this specification.

Control box' 36 houses a hurnidity indicator, the control humidostat or. humidostats, the control switch and the pilot light for the fan circuit, as will be discussed at greater length further on in thisspecification.

Fans 35 are preferably of the four: blade propeller type, '48 in diameter, driven bythree quarter horsepower electric motors through a V-belt drive. The I-LP. motors are preferably 208-220/440-volt, 3 phase, 60 cycle, 1725 rip.m., totally enclosed fan cooled. At full load motor speed of 1725 r.p.m.,the fans rotate at 336 rpm; and deliver 24,300 c.f.m. free delivery.

It will be noted from FIG. "1 thatthe canopy 10 is preferably free at its bottom lateral extremities -and is of such length as to lap over on the surface of the ground along the'bottorn lateral edges of the stockpile to seal the .bottom of canopy '10 against the surface of the ground adjacent the. stockpile 8.. As shown, the lower ends'of ;control ropes 18 and 1$are,aifixed at equal intervals along propriate keepers 22f'and'23 provided on vertical, poles 14 and 13, respectively; V v r The center or ridgepolesection of cover 10 is appropriately supported beneaththe ridgepole .and .cross bars 15 of frame 11 by means of a series of canvas loops provided at equal intervals down'its upper, median line receiving a pipe rnember'26 which'is passed longitudinally'therethrough. Pipe 26ispreferably formed of a, section of pipe and is preferably supported adjacent the middle of cross braces l5 by means" of a seriesof S;- hooks 27, fitted at their upper extremitiesover cross braces 15 and at their lower extremities about pole 26 to support cover 10 along is upper, median line beneath V the ridgepole of the frameyll, If desired, pole 26 may 'be boltedor lashed beneath cross braces 15. V r

' The forward, openextremity of .cover'ltl is'provide'd about its edges with aseries of rings 30, preferably three to each side, as shown, which are appropriately stitchedor otherwise aflixed thereto and through which is passed a binding or retaining 'line' 31 designed to hold the forward, lateral edges of cover 10 closely about the stack S, at its forward extremity; Binding line 31 is provided the lower ,lateral edge of canopy =10. It will thus be seen that when central ropes 181and1-9 arepulled upwardly through pulleys 16 and 17 the sides of canopy 10 will be progressively raisediuntil they are'furled'under. the

upper, lateral extremities of the framellwhen it is desired to remove the dried stockpile S or to pile newgreen lumber Within thefrarnean-d cover, prior to the drying operation' V a p i V 'As aforesaid, if the canopy-type structure is tube installed within a shed 'or otherty'pe of rectangularly walled and roofed structure the pulleys 16 andf17' may beappropriate'ly hung in pairs atthe desired interval, from, the

' 'walls. or roof of. the shed, and the canopy may then be installed therein by passing its control ropes 18 and 19 through theappropriate pulleys, the rear wall of the shed serving asthe housing fo-rfaris 35..

w An' alternative embodiment of the invention is illus- --troted iri FIGS..2,' .3, 4 and 5 of the drawings. This embodiment of the invention is particularly adapted to installation within a standing rectangular. structure comprising vertical sidewalls, a rear wall anda fixed roof. 'As

' shown, this embodiment contemplates the provision of a series of hinged bafile panels vertically disposed at equal intervals along the inner surfaceof the sidewalls of the building capable of swinging inwardly with respect thereto at its extremities with a snap and ring closure'm'eans 32 Y capable. of downward movement through an arc of 90.

whereby its two free ends are joined after being laced through rings 39 over the outer face of stockpile S. As

will 'be seen, removalfof binding line 31 from rings 30 frees the open extremity of cover 10 to permit cover 10 to be drawn upwardly clear ofthe stockpile S by means 1 to an angle of approximately 90 with respect to said side walla-and a further series of parallel and downwardly disposed hinged bafile panels disposed laterally across the width of the roof, between said vertical baffle panels, and

with respect thereto, as will be discussed in moredetail.

As shown in FIGS; 2 and 3 this air foil bafile embodiment of the invention comprises a series of preferably four :ventically disposed baflie panels 40 equally suitably aflixed toithe sidewalls and to the outer extremwood, plywoodorrnetal and which is supported between j the rearmost vertical poles 13 and 14 and appropriately braced therebetwe'en. Ifthe installation is setup within a shed or other roofed structure the 'rear-wall'of the l structure may beutilized in place of panel 35. p r p As will be seen from FIG. 1, rear panel '33 is prefer ably provided with a series of six'circular vents 34, alignedin two equal and parallel banks of three, in which are ities of 'bafile panels 40 in such fashion that baffle panels ifi'may swing inwardly withrespect to the lateral walls of the structure to an'angle of As shown, panels 40 are of appreciable width and are preferably formed of plywood or other appropriate material and extend vertically to substantially the full height of the side walls 42 of the structure. Y

At their inner extremities bafile' panels 40 are provided I and fully seated therein. through the looped section 49 of air foil 44 in alignment with looped air foil members 44, one of which is shown in cross-sectional detail in FIG. 4 of the drawings. Air foil baflies 44 are preferably formed of canvas or other appropriate flexible and inflatable material and are afiixed to the inner extremities of bafile panels 4t? by means of a transverse bolt 45, nut 46, washer 47 and a series of spaced separating blocks 48. As shown, the outer extremity of air foil baffle 44 is brought about into a longitudinally disposed loop 49 which is appropriately stitched along a vertical line at 50 to the body of the air foil 44 to provide a housing for a retaining bar 51, for-med of wood or other appropriate material, which is disposed within loop 49. Separating blocks 48 are provided at intervals down the length of the inner extremity of panel 46 to separate and space the looped extremity of air foil 44 and bar 51 an appropriate distance outwardly from the surface of bathe panel 49. As shown, blocks 48 are appropriately bored, as is bar 51 and the extremity of panel to allow passage of bolts therethrough at the spaced intervals where separating blocks 48 are placed to maintain air foil 44 in permanently looped condition at the extremity of panel 4% and to provide a series of equally spaced air access vents 52 between the looped extremity 49 of the air foil 44 and the surface of panel 40.

In assembling the air foil and panel structure the following steps are preferably taken. As aforesaid, panel 40 is appropriately bored adjacent its inner edge for passage of bolts 45. Retaining bar 51 is also bored at the same intervals and separating blocks 48 are bored for passage of bolts 45. Bar 51 is slid within loop 49 of air foil 44 Appropriate holes are then cut with the holes in bar 51 and a series of blocks 48 are then placed between bar 51 and the bored extremity of panel 4%). Bolts 45 are then passed through the registering holes in bar 51, blocks 48 and panel 4d. The opposite, free extremity 53 of air foil 44 is then placed over the threaded extremities of bolts 45, appropriate holes having been cut in extremity 53 for passage of the bolts. Washers 47 and nuts 46 are then applied over the screw threaded extremities of bolts 45, over the end 53 of air foil 44, and nuts 46 are then tightened down to maintain the entire assembly. Auxiliary screws 54 may then be inserted through the end of extremity 53, at intervals, to 'hold it closely against the outer surface of panel 46. The structure resulting from this operation is a looped air foil bag provided with a series of wide air entrance vents 52 along its open, outer extremity to receive and retain air I to inflate the air foil baffle and maintain it in inflated condition during operation of the fan bank located in the inner wall of the structure. It will be noted that the open I p 44 impinge against the outer surfaces of the stacked lumher and conform to the irregular contours thereof to seal off the lateral edges of the stack and prevent escape of air therearound. The top and bottom edges of air foil baffles 44 are preferably closed, by sewing or other means, to prevent escape of air.

As shown in FIGS. 2, 3 and 5, a similar air-foil baflie installation is provided under the roof of the structure I with the panels 66 and air foil baiiles 61 hingedly affixed by hinges 62 in parallel across the width of the roof and equally spaced from each other the length thereof, to seal off the upper surface of the lumber stack and prevent escape of air thereover when fans 56 are operating. These top air foil baffles 66-61 are constructed in pre cisely the same manner as the side wall air foil baffles 40-44, previously described. As shown, roof baflies 60-61 are so disposed in parallel with respect to each other that they alternate with and are equally spaced bebetween vertical bafiles 49-44 and fall between vertical baffles 40-44 when in lowered position. Here again, the open necks of air foils 61 are disposed outwardly toward the open end 55 of the enclosure to receive air drawn through the open end 55 of the enclosure by fans 56, disposed in its rear wall.

In FIG. 5 of the drawings there is illustrated one means of retracting ceiling bafiles 66-61 when not in use. The retracting means comprises a rectangular angle member 65, bolted at its upper extremity to the outer surface of panel 60 and extending downwardly and inwardly therefrom at a right angle, adjacent the side wall of the structure. A cable 66 is attached to 67 to the extremity of angle member 65 and passes thence over a vertically disposed pulley 68 suspended beneath the ceiling in a bracket adjacent the side wall and thence over a rectangularly disposed pulley 69 adjacent the side wall and also suspended from the ceiling in a bracket and thence passes laterally across the ceiling to the opposite side wall where it passes over a third, vertically disposed pulley 70, and thence downwardly to a weight 71 afiixed at its lower extremity. Weight 71 should be heavier than baffle 60-61. It will be seen that with weight 71 hanging free the bafiie 60-61 will be maintained in raised position aganst the ceiling on hinges 62 by means of cable 66 and angle member 65.

When it is desired to lower the ceiling baffles, weights 71 may be raised or removed from the extremities of cables 66 and the baffles will drop by gravity into a substantially vertical position, as shown in dotted lines in FIGS. 2, 3 and 5, whereby the lower surfaces of air foil bafiles 61 will impinge against the top surface of the lumber stack to seal it off and prevent escape of air thereover.

In view of the fact that the ceiling baflies 60-61 are equally spaced between vertically disposed side wall baffies 40-44, there is no possibility of interference or contact between the batlles during opening or closing thereof. Further, due to this alternation of the baffles, a very eflicient sealing of the lumber stack results. All bafiies are preferably on the order of 3 in width and are spaced some 6'4" apart, the ceiling baffles falling equidistant between vertical baffles 40-44.

The control box and circuit for the fan motors are illustrated respectively in FIGS. 7 and 8 of the drawings, the control circuit being schematically set out in FIG. 8.

Thus, in FIG. 7 is shown one embodiment of a control box 75 for the circuit including a humidity indicator 76 which reads relative humidity on a calibrated scale from 0% to and is provided on the control box for visual observation by the operator to check the operation of the control humidostat. The humidostat '77 controls the fan motor circuits, 78 is a single pole, double throw switch designated on, off, automatic. When switch 78 is in automatic position operation of the fan motors is controlled by the humidostat 77. In on position the humidostat 77 is cut out of the circuit and the fans operate regardless of humidity. In off position the fans are shut off for loading and unloading lumber from the enclosure. A pilot light 79 is included in the humidostat control circuit, as shown, and burns at all times When the humidostat calls for fan operation.

A schematic showing of the control circuit for the fan motors is shown in FIG. 8 of the drawings, 78 being the single-pole double-throw switch, 77 the humidostat and 79 the pilot light in the humidostat control circuit. A terminal strip for the circuit is indicated at 80, the fan motors at 81 and 82 designates suitable magnetic starters for the fan motors. Thus, with the switch in on posi tion the humidostat 77 will be cut out of the control circuit and the fan motors 81 will operate regardless of the humidity. With the switch in auto position the fan motors will operate under the control of the humidostat and in off position the fan motors will be shut down for loading and unloading the drying enclosure.

. rear extremity. v

' In the embodiment of the invention shown in FIGS. 2, 3, 4 and 5, in which swinging wall and ceilingair foil i The humidostat' shown at 7'7'is preferably a high level humidostat designed to maintain motorfoperationup to approximately 80-90% relative humidity," atwhichpoint the humidostat control will break the circuit to the fan motors and shut off fan'operation. If desired, a' second, 7

The magnetic starters 82 for the'fan' motors. 81" are shown schematically andare of standard and well known type serving to make the starting of the motors aigradual operation and prevent undue'initial acceleration thereof.

As previously indicated, the control box75 for the motor circuit may be placed in any convenient location a where it will be readily accessible to the operator.

In the embodiment of the inventionshown in FIG. 1

the canvascanopy ltl is preferably rectangular in shape" and of such dimensions that it will closely embrace the" side and'top surfaces of .the lumber stack S when in lowered and lashed position 'to insure' that the air drawn down through the canopy 1d by the bank of fans 35 will impinge equally against'all surfaces of the stacked lumber] to afforda uniform and constant drying thereof, eliminat- 8 that dryingwill be uniform and as rapid as is desired to I produce an optimum drying in the lumber stack;

' j It should be emphasized that with the present system of drying the moisture content is lowered inall: theboards jinjthe, stack uniformly andat a constant rate toprevent warp and twist and to insure equal and uniform drying.

When it is desired to remove the lumber from'the canf .opy of theembodiment shown in FlG gl, the canvascover 10 its-pulled upwardly'by means of control ropes 18 and 19, affixedadjacent its lower lateral extremities, until the 1 entire cover israised freetabove theistack. The lumber max then be'removedat will; A new stack may then be set within t e framework and the canopy 10 may then be ing warping, splitting and checkingxof the lumber and assuring efiicient preliminary drying thereof within a' periodof'fr'om-S to 10 days; Preferably, thelumber stack will been the order of 18'feet in width, by l2 feet in height and not over feet in depth, from the .open forward extremity of the canopyj10 to the fan panel 33 at its baffles are utilized in place of the canopy, a lumberstack of substantially the same dimensions, i.e.'- 18 x 12 x 30,

is first formediwithin the walled enclosure withthe individual layers of boards :preferably separated by appro priate spacers to allow passage of air over all surfaces 7 thereofequally. Withthe-lumber' stack so setup, the side bafiles 40-44 are then swung inwardly on their hinges 41 until. theinner surfaces of the air foil bailles 44 are in l'released; to fall downwardly andclosely engage'the outer isurfaces of the lumber stack,'prior to'.the initiation of the.

new drying cycleq Asgaforesaid, prior to'raising of the j canopy 1t) by control ropesIS and 19 the front binding rope 31 should be untied and removed from rings 3-0 to ree theforward, open extremity of the cover. Conversely, after the cover 10 is dropped over a new, green stack, with'its lower lateral, edges 'in contact with the surface of" the ground, binding cord 31 should be repassed through rings sass shown in FIG, 1, and clinched at 32'to' maintain the forward extremity of the cover in close engagement'about the lumber stack. v

In the embodiment shown in FIGS. 2' and 3, when the r lumber stackis 'suiiicientlydried the fan motors are turned off by switch 78, the lateral baffles 40-44 are then swung inwardly against the side walls until they areflush therewith. The ceiling baffles 68-61 are then pulled upwardly to flush position with the ceiling,iby cords o and weights i "71,; as shown'in FIG. 5., and'the lumber may then be removed and anew stack placed within the enclosure, without interference from the side and ceiling bat-ties.

As aforesaid, with the installation here illustrated the length ofthe preliminary drying time forlumber is 'drasticallyreducedto from five to'ten days'from the conventional yard'p'eriod of three toffour months, A

' highly-supefior product is evolved, warpage, twisting, end

checks and stains being eliminated due to the provision of uniform velocity of air at the proper humidity over all surfaces of the stockpile of g'reenlumber. J

firm contact with the lateral'edges of the lumber stack to.

seal off the lateral edges and prevent the'escape of air thereabout. The roof or ceilingbafiles -61 are then lowered into position by the raising or removal of control a a weights 71 from cables 66 until thelower surfaces of air foil baffles-61 impinge againstthe upper surfa'ceof I the lumber stack, to seal off the upper surface of the stack .to the escape. of air thereover.

conformable nature of air foilbaffle members'l44 and 61 the impinging surfaces-thereof will conform to irregularities in'the' surface of the lumber stack'to assure a perfect seal, as shown in'FIG. 4 of the drawings.

When the air foil baffles thus rextended inwardly into close and conforming contact with the side and top surfaces of the lumber stack the control switch 78 is thrown i to automatic position, bringinghumidostat 77 into control of the-motor circuit, the fan motors are. started through the magnetic starters'82 and the fan bank begins operation drawing air through the openextremityfe'iof' the building. ,This air is pulled into contact withthe wall and ceiling air foil bafiles and inflates the loopedflexibley extremities 44 and 61 thereof to holdtheir Zinner .surfaces rigidly and conformably in contact with the lateral and upper surfaces of thejlumber stack. It will thus be seen that thejlumber stack is fully'sealed along both sides and its top against the escape ofair thereoverj Thus,

substantially the full volum'e of air drawn through the enclosure bythe fans '56 will pass in uniform flow through Due to the flexible and 1 With the present installation the speed of drying may be controlled by varying the fan speed to control the volume'and velocity of theair, stream through the stockpile. Thus, if fan speed is reduced to one half maximum speed, volume. and velocity of air passed through the stockpile will be cut in half and drying time doubled.

With the installation shown, on the order of 129,000 cubic feet of air per minute are pulled through the stockpile at a uniform velocity. A single installation. of the .size and capacity indicated,.is capab1e of dryingover a million board feet of one] inch 'thicklumber a year.

After the initial drying in the. subject installation the lumber is in perfectcondition for final drying inthe kilns and a vastly superior finally dried product is the result. The invention is susceptible of numerous modifications without departing from the spirit thereof. Thus, the di- I11I1SlOIlS'Of the enclosure may be varied. within wide said fans, a 'circuit'including a ,humidostat to control said her being dried and the 'sizeof 65 limits. 'Thetype' and number of fans used may also be changed,- as required. The control circuit may be modified, as desired,'and the number and 'dispositi'on'of the baffies shown in the second embodiment of the invention may be 'varied at will, depending upon the type of lumthe enclosure being used. What is'cl'aimed is: i 1. In' an installation for drying lumber, arectangular enclosure comprising side and' rear wallsand a roof and open at its front extremity designed to contain a stack of lumbenflafseries of .evenly'disposedfans mounted in said rear wall'to pullfiairthrough said enclosure, motors for motors in accordance with atmospheric humidity, a series of verticall 'dis 0 ed," the lumber stack at a constant velocity, witho t. 1 p S mwardly SWlnglng bames hmgadly about the edges thereof This shielding vprovision insures mounted on said side walls, loopedfabric 'air foil members afiixed at the inner extremities of said-bafl'les open to and inflatable by the air stream at their forward, inner edges and contacting the lateral walls of said stack of lumber, downwardly swinging 'baflles hingedly mounted in parallel beneath the roof of said enclosure, looped fabric air foil members open to the air stream at their forward, inner edges afiixed to the inner extremities of said baffles and contacting the upper surface of said stack of lumber when said baflies are in lowered position whereby air at desired humidity will be pulled at a constant velocity through the stack of lumber and will be prevented from escaping around said stack by said bafiies and inflatable air foils.

2. In an installation for drying lumber, an enclosure comprising side and rear Walls and a roof and open at its front extremity designed to contain a stack of lumber, a series of evenly disposed fans mounted in said rear wall to pull air through said enclosure, motors for said fans, a circuit including a humidostat to control said motors in accordance with atmospheric humidity, vertically disposed and evenly spaced, inwardly swinging baflles hingedly mounted in parallel on said side walls, tubular flexible air foil members afiixed at the inner extremities of said battles open to the air stream at their forward inner extremities and contacting the lateral walls of the stack of lumber, downwardly swinging battles hingedly mounted in parallel beneath the roof of said enclosure, looped flexible air foil members open to and inflatable by the air stream at their inner, forward extremities affixed to the inner extremities of said baffles and contacting the upper surface of the stack of lumber when said battles are in lowered position whereby air at desired humidity will be pulled at a constant velocity through said stack of lumber and will be prevented from escaping around said stack by said baffles and inflatable air foils.

3. In an installation for drying lumber, an enclosure comprising side and rear walls and a roof and open at its front extremity to contain a stack of lumber, two parallel rows of fans mounted in said rear wall to pull air through said enclosure, motors for said fans, a circuit including a humidostat to control said motors in accordance with atmospheric humidity, a series of vertically disposed, inwardly swinging baffles hingedly mounted in parallel on said side walls, tubular, looped fabric air foil members affixed at the inner extremities of said baffles open to the air stream at their outer extremities and contacting the lateral walls of the stack of lumber, downwardly swinging bafiles hingedly mounted in parallel beneath the roof of said enclosure, tubular, looped fabric air foil members amxed to the inner extremities of said bafiies open to and inflatable by the air stream at their upper extremities and contacting the upper surface of the stack of lumber when said battles are in lowered position whereby air at desired humidity will be pulled at a constant velocity through the stack of lumber and will be prevented from escaping around said stack by said bafiles and inflatable air foils.

4. In an installation for drying lumber, an enclosure comprising side and rear walls and a roof and open at its front extremity to contain a stack of lumber, a parallel series of evenly disposed fans mounted in said rear wall to pull air through said enclosure, motors for said fans, a circuit including a high level humidostat to control said motors in accordance with atmospheric humidity, a series of vertically disposed, inwardly swinging bafiies hingedly mounted in parallel on said side walls, looped inflatable fabric bag members open to the air stream at their forward extremities affixed at the inner extremities of said baflles and contacting the lateral walls of the stack of lumber, downwardly swinging baiiies hingedly mounted in parallel beneath the roof of said enclosure, looped fabric bag members open at their inner extremities to the air stream and inflatable thereby afiixed to the inner extremities of said baiiles and contacting the upper surface of the stack of lumber when said baffles are in lowered position whereby air at desired humidity will be pulled at a constant velocity through said stack of lumber and will be prevented from escaping around said stack by said baflies and inflatable air foils.

References Cited by the Examiner UNITED STATES PATENTS 97,777 12/69 Johnson 34-229 X 1,432,248 10/22 Hirt 34-231 X 1,804,107 5/31 Mueller 34-230 2,767,484 10/56 Gilson 34-54 NORMAN YUDKOFF, Primary Examiner. 

1. IN AN INSTALLATION FOR DRYING LUMBER, A RECTANGULAR ENCLOSURE COMPRISING SIDE AND REAR WALLS AND A ROOF AND OPEN AT ITS FRONT EXTREMITY DESIGNED TO CONTAIN A STACK OF LUMBER, A SERIES OF EVENLY DISPOSED FAND MOUNTED IN SAID REAR WALL TO PULL AIR THROUGH SAID ENCLOSURE, MOTORS FOR SAID FANS, A CIRCUIT INCLUDING A HUMIDOSTAT TO CONTROL SAID MOTORS IN ACCORDANCE WITH ATMOSPHERIC HUMIDITY, A SERIES OF VERTICALLY DISPOSED, INWARDLY SWINGING BAFFLES HINGEDLY MOUNTED ON SAID SIDE WALLS, LOOPED FABRIC AIR FOIL MEMBERS AFFIXED AT THE INNER EXTREMITIES OF SAID BAFFLES OPEN TO AND INFLANTABLE BY THE AIR STREAM AT THEIR FORWARD, INNER EDGES AND CONTACTING THE LATERAL WALLS OF SAID STACK OF LUMBER, DOWNWARDLY SWINGING BAFFLES HINGEDLY MOUNTED IN A PARALLED BENEATH THE ROOF OF SAID ENCLOSURES, LOOPED FABRIC AIR FOIL MEMBERS OPEN TO AIR STREAM AT THEIR FORWARD, 